I’ve just started brewing and am gathering an equipment list for a 5 gallon all grain system and have a few questions:

1) The AG porter I brewed was a one step mash infusion – will this technique limit my future brewing choices?

2) I am leaning towards a 5 gallon Gott cooler mash/lauter tun, but would like to know if a kettle with spigot would be better for any reason. The kettle seems better for step mashing, but I’m not sure if I will need this technique (see question #1). The cooler seems better at maintaining a constant temp.

3) If I go with the cooler tun, is there a consensus on whether to use a false bottom or an EZ mash sytem? EZ mash seems to work better – is this true? What about just using grain bags?

4) I will be brewing 5 gallon batches, so should I get a 6.5 gallon carboy to ferment in to avoid blow out?

5) Similar question for the brew pot – is 8 gallons the size to use if I am using an immersion wort chiller?

Thanks for your insight, and please feel free to fill me in on anything I should know!

I wasn't sure if this should go in the equipment section, and don't know if cross posting is frowned upon here, so sorry if this is the wrong forum.

1) no, step mashing works fine, I've used it for every beer I've made: belgians, wits, hefes, ales, stouts, porters.
2) get a bigger cooler, I say 7-8 gal cooler, 10 is even better.
3) I recommend a copper manifold with a rectangular cooler, I've never had a stuck sparge even with a 70% wheat grain bill.
4) Yes, you want some headspace
5) I use an 7.5 gal brewpot, it's too small, but doable. if you can get 8+ that would work great, and I use an immersion chiller on my 7.5 gal turkey fryer pot.

Go with a manifold. Cheap, DIY and no stuck sparges:
I used a 5 gallon cooler when I did 5 gallon batches. If yo have an axtra $10.00, step up to a 10 gallon. If not, the 5 gallon works great.

Definitely want enough head space for any potential blow offs. I don't care much about watching my beer "perform" anymore, so I use the 7.5 gallon buckets to primary, but the 6.5 glass will do the trick:

I had the 7.5 gallon turkey fryer pot and it worked just fine for 5 gallon AG's with and immerison chiller:

You didn't say if you are intending to batch sparge or fly sparge. That actually changes the recommendations a bit. If you are fly sparging, having a lot of cooler space isn't as imporant. Batch spargers need the extra room because they are adding all or much of their sparge water at one time so the cooler MLT must accommodate it. That is why you see so many people advocate a 10 gal cooler if you batch sparge. I have had no problems with grainbills as small as 6.5 lbs and up (for a 5 gal batch, you should be able to get about 25 lbs of grain in there, for a ridiculously high OG beer, if you wanted).

I don't have much experience fly sparging, so I can't comment on the choice of manifold vs. false bottom, etc. But for batch sparging, the absolute cheapest and easiest solution is a $5 braid. No work, and lots of people swear by them. For five bucks and almost zero time to install, it might be worth a try.

Regarding infusions, a lot of noteworthy brewers are highly advocating single infusions for most beers. But there will always be some beers that are going to require something more. With a cooler mash tun, you can always do decoctions, if you have the time and interest, or you can find alternate ways to do a step mash (e.g., multiple water infusions, steam infusion).

Did the 10 gal cooler have any problems maintaining temp for 5 gallon batches?

Is the mainfold something most beer shops stock?
(No work space or tools to make one)

My 10 gallon Gott cooler holds temps perfectly. I do preheat with hot water first, though. Most LHBS stock a Phils false bottom. I got mine from morebeer.com and I've never had a problem. I wanted a copper manifold but I'm mechanically challenged so I needed to buy something and I'm happy with it. Here is mine: http://morebeer.com/view_product/15571/
Unfortunately, I see it's currently out of stock, but you might find it somewhere else. It uses a little piece of plumbing (soft) tubing to connect to the bulkhead fitting. So far, no stuck sparges, and my cooler has never been maxed out for any of my 5 gallon batches, even the higher sg ones.

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